Electrical-circuit protector.



C. A. ROLFE.

ELECTRICAL CIRCUIT PROTECTOR.

APPLICATION FILED DEC.29,1903.

RBNEWBD PBB.13, 1908.

Patented Sept. 15, 1908.

UNiTEDsTATEs rniinvii omnes.

CHARLES A. ROLFE, OF ADRIAN, MICHIGAN, ASSIGNOR, BY MESNE ASSIGNMENTS,TO ROLFE ELECTRIC CO., OF ROCHESTER, NEW YORK, A CORPORATION OF NEWYORK.

ELECTRICAL-CIRCUIT PROTECTOR.

Specification of Letters Patent.

Patented Sept. 15, 1908.

Application led December 29, 1903, Serial No. 187,044. Renewed February13, 1908. Serial No. 415,763.

To vall whom 'it may concern.

Be it known that I, CHARLES A. ROLFE, a citizen of the United States,residing at Adrian, in the county of Lenawee and State of Michigan, haveinvented a certain new and useful Improvement in Electrical- CircuitProtectors, of which the following is a full, clear, concise, and exactdescription, reference being had to the accompanying drawings, forming apart of this speciiication.

My invention relates to devices for rotecting low tensioncircuits suchas te egraph, fire-alarm and the like, from injurious effects of undulystrong currents such as those carried by power and lighting circuits.

Prominent objects of the invention are to rovide a simple, ractical andinexpensive orm of protector olf3 this kind; to make it unnecessary forthe device to be repaired or have its parts replaced after operation andto accomplish the foregoing results in a practical and expeditiousmanner.

In the accompanying drawing, Figure 1 is a side elevation of aprotective devicev embodying my present invention; Figs. 2 and 3 arelongitudinal and horizontal-sections of a portion of such device, Fig. 2showing the device unoperated and Fi 3 after operation; Fig. '4 is anend view o the device; Figs. 5 and` 6 are respectively a longitudinal,horizontal section, and an end view of a modified form. l

Referring to the arrangement shown in Figs. 1 to 4 inclusive, 1 is abase made of insulating material such as wood, porcelain or the like. Uon this is mounted a pair o f line sprin s 2 an 3 which tend to springor separate om one another and are constructed with forked u per ends.These s rings carry or support a eat cartridge 4 wliiich is constructedas best shown in Figs. 2 and 3. It comprises a metallic terminal 5having a head 6 and an insulating sleeve 7 having one end fitted in theterminal 5. A pair of leaf or flat springs 8, 8, are arranged within theinsulating sleeve 7 and have their inner ends embedded and secured inthe end of the sleeve 7. These springs tend to se arate from one anotherand assume the iverging position shown in Figs. 2 and 3. Outside of thes rings 8, 8, is arranged a metallic thimble or s eeve 9 and about thisis coiled a coil of insulated wire 10. The springs 8, 8, are solderedalong their outer faces as indicated at 11, 11,

mally in their separated condition. The coil 10 has one of its endsconnected with one of the springs 8 and the other end connected with theterminal 5 so that the circuit is completed through the coil, thesprings 8, 8 and the line springs 2 and 3. This heat cartridge is somounted upon thesprings 2 and 3 that the head 6 is engaged by the spring2 and the springs 8, 8, by the spring 3.

The' operation of the device is as follows. Under normal conditions theheat cartridge is sustained by the two springs 2 and 3 as shown in Figs.1 and 2, the cartridge in turn holding the springs under restraint. Solong l as the current in the circuit under rotection is normal, thedevice remains in t 's condition. When however it becomes unduly strong,suflicient heat is generated by the coil 10 to soften or melt the solder11, 11, whereupon the outward tension of the springs 2 and 3 causes thesprings 8', 8, to be com ressed together by the s ring 3 with the re'sut that the spring 3 s ides along the springs 8, 8, and passes oif theends thereof as shown in Fig. 3, the position of the springs 2 and 3after operation being indicated in dotted lines in Fig. 1. In this waythe circuit is opened by the separation of the spring 3 from the ends ofthe springs 8, 8. As soon as this separation occurs, 'the springs 8, 8,immediately spring away from each other back into their normal divergingposition, and upon assuming this osition the solder 11, 11, againbecomes ardened, thereby` holding the springs in that position.

In the arrangement shown in Figs. 5 and 6, a base and a air of linesprings 2 and 3 are provided as efore. The heat cartridge supported bythe springs 2 and 3 comprises a terminal 5 constructed with a head 6 andan insulating plug or bushing 12 inserted and secured in the terminal 5.A pair of s rings 13, 13 are embedded at one end in thepbush- -ing 12and extend outwardly so that their outer ends engage the forked end ofthe spring 3. These s rings 13, 13 tend to separate from one anot er andassume and maintain the diverging condition shown in Fig. 5. Betweenthem is a body or mass of solder 14 and arranged about them is a coil ofwire 15. One end of this coil of wire ,is connected to one of the srings 13, 13, and the other end is connecte with the metallic terminal5. Thus the circuit is made from one line spring to the thimblev9 sothat they are held nori' to the other, through the heat cartridge by wayof the springs 13, 13, the coil 15 and the terminal 5. The operation ofthis device is combination of a pair of line springs, a heatsubstantially that of the foregoing device, the sprin s 13, 13, beingheld normally apart by the so der 14, and being compressed when suchsolder is softened by the coil 15 so as to allow the release of thespring 3 by the springs 13, 13. As soon as the spring 3 is separatedfrom the springs 13, 13, the latter resume their original divergingcondition and the solder 14 thereupon hardens, resoldering such springsin that condition.

From the foregoing it will be seen that when either form of device isoperated, it is not necessary to renew any of the parts or to repair itin any way. rlfhe heat cartridge springs engaging the line srrings, byautomatically restoring themse ves to normal condition and beingresoldered in such condition, place the cartridge in shape to be re-lengaged by the line springs, ready for another operation. This, it willbe seen, happens after e'very operation of the device, so that it canoperate time after time without any expense or inconvenience of repairsor reglacements.

t will be understood that changes and modifications can be made in theforms of devices herein set forth, without de arting from the spirit ofmy invention, and algo that other forms can be devised embodying theinvention.

What I claim as my invention is 1. In apparatus of the class specified,the combination of a pair of line springs, a heat cartridge supported bysaid line springs, and comprising spring members subjected to thetension of the line springs, softenable material holding said springmembers ,normally against such tension, and a heat concentrating deviceadapted to soften or melt said softenable inaterial, substantially asdescribed.

2. In apparatus of the class specified, the

cartridge supported thereby,- and comprising a air of springs tending tomove or spring in a ateral direction and engaged by one of said linesprings, softenable material holding said cartridge springs against suchlateral action, and a heat concentrating device ada ted to melt orsoften said material, substantially as described.

3. In apparatus of the class specified, the combination of la pair ofline springs, a heat cartridge supported thereby, and comprising a pairof flat springs tending to spread or separate from one another, saidsprings being engaged by one 0f the line springs, softenable materialada ted to hold said cartridge springs in suc i spread condition, and aheatY coil ada ted to soften or melt such softenable materiasubstantially as described.

4. In apparatus of the class specified, the

combination of a pair of line springs having forked ends, said linesprings tending norl mally to separate from one another, a heatcartridge supported by said springs and comprising a metallic terminalhaving a head for engaging one of the line springs, a pair of leafsprings tending to spread or separate from one another, said springsbeing in engagement with the forked end of the other' line spring, aquantity of solder normally holding said springs in their spreadcondition, and a heat coil associated with said solder for melting orsoftening the same, substantially as described.

5. In a thermal circuit-protector, in combination, a fixed member 5 aspring a springfinger fixed with relation to said fixed meinber andtending to lie in contact therewith, which finger is adapted to holdsaid spring exed, said spring tending to separate the spring-finger fromsaid fixed member; and a solder connection between said fixed member andsaid spring-finger,

6. In a thermal circuit-protector, in combination, a fixed member; aspring 5 a springfinger xed with relation to said fixed member andtending to lie in contact therewith, which finger is adapted to holdsaid spring flexed, said spring tending to separate the spring-fingerfrom said fixed member a solder connection between said fixed member andsaid spring-finger and a substance offering comparatively highresistance to the passage of an electric current, in proximity to saidsolder connection. v

7. In a thermal circuit-protector, in combination, two ears; aspring-finger adapted to lie in contact with each one of said ears; aspring adapted to be held flexed by said spring-fingers and tending toseparate said spring-fingers from said ears; and a fusible solderconnection between each one of said ears and its sprin -finger.

8. In a therma circuit-protector, in combination, two ears; a spring; aspring-finger adapted to lie in contact with each one of said ears andto hold said spring flexed, said spring tending to separate thespring-fingers from said ears; and a fusible solder connection betweeneach of said ears and its springfinger.

9. Ina thermal circuit-protector, in combination, two ears; a sprin aspring-finger adapted to lie in contact wifIi each one of said ears andto hold said spring fiexed. said spring tending to separate thespring-fingers from said ears; a fusible solder connection between eachof said ears andits springfinger; and a vsubstance oHering comparativelyhigh re'sistance to the passage of an electric current, in proximity tosaid solder connection.

10. In a thermal circuit-protector, in combination, a fixed member; aspring; va springfinger fixed with relation to said fixed member andtending to lie in contact therewith, which finger has a projectionadapted to engage said spring to hold the latter fiexed, said projectionalso causing said spring to tend to separate said spring-finger fromsaid fixed member; and a fusible solder connection between said fixedmember and said spring fin er.

lgl. In a thermal circuit-protector, in combination,axed member;aspring; a springfinger fixed with relation to said fixed member andtending to lie in contact therewith7 which finger has a Irlirojection`adapted to engage said spring to old the latter flexed, said projectionalso causing said spring to tend to separate said spring-finger fromsaid fixed member; a fusible solder connection. between said fixedmember and said springfinger; and a substance offering comparativelyhigh resistance to the passage of an electric current, in proximity tosaid solder connection.

l2. In a thermal circuit-protector, in combination, two ears; a pair ofspring-fingers having inclined outer ends, said fingers adapted to liebetween said ears, each of said fingers contacting one "of the ears; afusible solder connection between each one of said ears and itsspring-finger; and a spring having an opening adapted to receive theouter ends of said spring-fingers, said spring being held flexed by saidfingers when the fingers are held' by said solder connection'but tendingto separate said fingers from said ears.

n witness whereof, I hereunto subscribe my name this 16th day ofNovember A. D., 1903.

" CHARLES A. ROLFE.

Witnesses:

A. MILLER BELFIELD, I. C. LEE.

